Google Chrome reports the Apple M1 GPU if found. Other browsers just report: Apple GPU (same as on MacIntel based machines)
If the M1 GPU is detected in Google Chrome it will turn red. Otherwise it will report in red that this is not Chrome detecting an M1 GPU.

Apple M1 Mac GPU Detected on Chrome Browser
Not Apple M1 or Not Chrome Browser

GPU Detection Source:

Class injection test by Jeff Clayton

Test Site 1:
Test Site 2: